Siloxane-oxyalkylene copolymer foam stabilizers



United States Patent 3,505,377 SILOXANE-OXYALKYLENE COPOLYMER FOAMSTABILIZERS Edward L. Morehouse, Snyder, N.Y., assignor to Union CarbideCorporation, a corporation of New York No Drawing. Filed Aug. 12, 1966,Ser. No. 573,133 Int. Cl. C07f 7/08 US. Cl. 260448.2 6 Claims amolecular weight of at least 1500, x is at least 40, and y is at least3.

This invention relates to novel siloxane-oxyalkylene block copolymersand to the use of such copolymers as foam stabilizers for flexiblepolyurethane foams.

Flexible polyether urethane foams are conventionally prepared by a onestep or one shot process which involves reacting a polyisocyanate with apolyether containing hydroxyl groups in the presence of water, a blowingagent, catalysts (e.g. tin catalysts) and a siloxane-oxyalkylene blockcopolymer foam stabilizer. Of these various materials, one of the moreexpensive on a pound for pound basis is the siloxane-oxyalkylene blockcopolymer. Accordingly, it is desirable from an economic standpoint tominimize the amount of the block copolymer employed while retaining goodfoam quality.

In producing such foams, it is also desirable to control the formationof closed cells as an excess of closed cells impairs the breathabilityof the foam.

Over the past several years, a variety of siloxane-oxyalkylene blockcopolymers have been proposed as foam stabilizers for the production offlexible polyurethane foam. The first variety had a silicon to oxygen tocarbon linkage between the siloxane and oxyalkylene blocks. This linkageis hydrolytically unstable to some extent and so later varieties ofblock copolymers were characterized by a more stable silicon to carbonlinkage between the blocks. However, even the most recent varieties ofblock copolymers proposed are not entirely satisfactory. Thus somerequire relatively unavailable starting materials (e.g.dirnethylchlorosilane). Other block copolymer foam stabilizers must beused in relatively large amounts and are consequently costly. Stillothers, although allegedly hydrolytically stable, undergo some changewhen premixed with water and stored for prolonged periods with theresult that the foams produced contain excessive closed cells and,consequently, poor breathability. Yet other block copolymer foamstabilizers have poor tin operating latitude (i.e., they produce foamshaving poor breathability when used with normal concentrations of tincatalysts and, when the tin catalyst concentration is lowered to improvethe breathability of the foam, the foam becomes weak and containssplits).

It is an object of this invention to provide siloxaneoxyalkylene blockcopolymers which can be produced from readily available startingmaterials, which have good tin operating latitude and which can beemployed, even atfer admixing with water and prolonged storage, inrelatively small amounts to produce breathable flexible polyurethanefoam.

Other objects of this invention will be apparent from the followingdescription.

"ice

bon atoms), m and n are numbers, the sum of m-l-n is such that theoxyalkylene block,

has a molecular weight of at least 1500, from 15 to 60 weight percent ofthe oxyalkylene units are oxyethylene units, x has a value of at least40 (preferably at least 50 or 70), and can have a value up to 200(preferably up to or y has a value of at least 3 (preferably from 4 to15), the siloxane block constitutes from 15 to 70 weight percent of theblock copolymer, and Me is a methyl group.

Typical of the groups represented by R in Formula A are the alkyl groups(e.g. the methyl, ethyl, propyl and butyl groups), the aryl groups (e.g.the phenyl and to-lyl groups) and the aralkyl groups (e.g. the benzyland betaphenylethyl groups). Typical of the groups represented by R inFormula A are the ethylene, propylene, butylene and arnylene groupsvThis invention also provides a process for producing a flexiblepolyurethane foam which comprises reacting and foaming a reactionmixture of:

(I) A polyether or a polyester containing an average of at least twohydroxyl groups per molecule;

(II) A polyisocyanate containing at least two isocyanato groups permolecule, said polyether or polyester and said polyisocyanate, takentogether, being present in the mixture in a major amount and saidpolyether or polyester and polyisocyanate being present in the mixturein the relative amount required to produce the polyurethane foam;

(III) A blowing agent in a minor amount suflicient to foam the mixture;

(IV) A catalytic amount of a catalyst for the reaction of the polyetheror polyester and the polyisocyanate to produce the polyurethane; and

(V) A fioam stabilizing amount of a siloxane-oxyalkylene block copolymerrepresented by Formula A above.

The siloxane-oxyalkylene block copolymers of this invention are readilyproduced by the well known processes, e.g. by an addition reactionbetween a siloxane having SiH groups and an alkenyl end-blockedoxyalkylene polymer (polyether). The reaction is conducted by heatingthe reactants in the presence of a platinum catalyst (e.g. finelydivided elemental platinum supported on alumina or charcoal orchloroplatinic acid).

The polyesters employed in this invention to produce polyesterpolyurethane foams are the reaction products of polyfunctional organiccarboxylic acids and polyhydric alcohols. The polyesters contain atleast two hydroxyl groups per molecule (as alcoholic OH or as OH in COOHgroups). The polyesters can have hydroxyl numbers from 45 to 150 butpreferably have hydroxyl numbers from 45 to 65. These hydroxyl numbersare readily determined according to the procedure described by Mitchelet al.,' Organic Analysis, volume I, Interscience, New York, 1953. Thepolyesters can be free of aliphatic carbon to carbon multiple bonds(i.e.-olefinic double bonds or acetylenic triple bonds).

Typical of the polyfunctional organic carboxylic acids that can beemployed in producing polyesters useful in this invention aredicarboxylic aliphatic acids such as succinic, adipic, sebacic, azelaic,glutaric, pimelic and suberic acids and aromatic dicarboxylic acids suchas phthalic acid, terephthalic acid, isophthalic acid and the like.Other polycarboxylic acids that can be employed are the dimer acids suchas the dimer of linoleic acid. Hydroxyl-containing monocarboxylic acids(such as ricinoleic acid) can also be used. Alternatively, theanhydrides of any of these various acids can be employed in producingthe polyesters.

Typical of the polyhydric alcohols (polyols) that can be employed inproducing the polyesters useful in this invention are both the monomericpolyhydric alcohols (such as glycerol, 1,2,6-hexanetriol, ethyleneglycol, trimethylolpropane, trimethylolethane, pentaerythritol,propylene glycol, 1,3-butylene glycol and 1,4-butylene glycol) and thepolymeric polyhydric alcohols (polyethers) such as those describedbelow.

The polymeric polyhydric alcohols employed in producing the polyestersused in this invention include the linear and branched chain polyetherswhich have a plurality of acyclic ether oxygens and contain at least twoalcoholic hydroxyl radicals. Illustrative polyethers include thepolyoxyalkylene polyols containing one or more chains of connectedoxyalkylene radicals which are prepared by the reaction of one or morealkylene oxides with acyclic and alicyclic polyols. Examples of thepolyoxyalkylene polyols include the polyoxyethylene glycols prepared bythe addition of ethylene oxide to water, ethylene glycol or dipropyleneglycol; polyoxypropylene glycols prepared by the addition of propyleneoxide to water, propylene glycol or dipropylene glycol; mixedoxyethylene-oxypropylene polyglycols prepared in a similar mannerutilizing a mixture of ethylene oxide and propylene oxide or asequential addition of ethylene oxide and propylene oxide; and thepolyoxybutylene glycols and copolymers such as polyoxyethyleneoxybutylene glycols and polyoxypropyleneoxybutylene glycols. Included inthe term polyoxybutylene glycols are polymers of 1,2- butylene oxide,2,3-butylene oxide, and 1,4-butylene oxide.

Other acyclic and alicyclic polyols which can be reacted With ethyleneoxide, propylene oxide, butylene oxide or mixtures thereof to providepolyethers that are use- 1.11 in producing polyesters used in thisinvention include glycerol, trimethylolpropane, 1,2,6-hexanetriol,pentaerythritol, sorbitol, glycosides, such as methyl, ethyl, propyl,butyl and 2-ethylhexyl arabinoside, xyloside, fructoside, glucoside andrhammoside, and polyethers prepared by the reaction of alkylene oxideswith sucrose.

Further polyethers that are useful in producing polyesters that can beused in this invention are prepared by reacting a 1,2-alkylene oxidesuch as ethylene oxide, propylene oxide, butylene oxide or mixturesthereof with mononuclear polyhydroxybenzenes such as resorcinol,pyrogallol, phloroglucinol, hydroquinone, 4,6-di-t.-buty1- catechol orcatechol. Other polyethers which can be employed in producing polyestersthat can be used in this invention are those obtained by reacting1,2-alkylene oxides or mixtures thereof with polynuclear hydroxybenzenessuch as the various di, triand tetraphenylol compounds in which two tofour hydroxybenzene groups are attached by means of single bonds or byan aliphatic hydrocarbon radical containing one to twelve carbon atoms.The term polynuclearas distinguished from mononuclear is used todesignate at least two benzene nuclei in a compound. Exemplarydiphenylol compounds include 2,2 bis(p hydroxyphenyl)-propane;'bis(p-hydroxyphenyl)-methane and the various diphenols and diphenylolmethanes disclosed in United States Patents Nos. 2,506,486 and2,744,882, respectively. Tetraphenyl- 01 compounds can also be reactedwith 1,2-alkylene oxides to produce polyethers that are useful inproducing polyesters that can be used in this invention. Otherpolyethers which can be employed in producing polyesters that can beused in this invention are the ethylene oxide, propylene oxide andbutylene oxide adducts of phenolformaldehyde condensation productmaterials such as the novolaks.

The polyethers employed in this invention to produce polyether urethanefoam include the polyethers described above as reactants for makingpolyesters.

A variety of organic polyisocyanates can be employed in this inventionfor reaction with the polyesters or polyethers above-described toproduce polyurethane foams. Preferred are polyisocyanates having thegeneral formula:

wherein i is an integer of two or more and Q is an organic radicalhaving the valence of i. Q can be substituted or unsubstitutedhydrocarbon group (e.g. an alkylene or an arylene group). Q can be agroup having the formula Q'ZQ' where Q is an alkylene or arylene groupand Z is O, -O-QO, CO, -S, S--Q'-S, or SO Examples of such compoundsinclude hexamethylene diisocyanate, 1,8-diisocyanato, pmethyl xylylenediisocyanate, (OCNCH CH CH OCH 1-methyl-2,4-diisocyanatocyclohexane,phenylene diisocyanates, tolylene diisocyanates, chlorophenylenediisocyanates, diphenylrnethanei,4-diisocyanate, naphthalenel,5diisocyanate, triphenylmethane-4,4',4"-triis0cyanate, andisopropylbenzene-alpha-4-diisocyanate. Further included among theisocyanates useful in this invention are dimers and trimers ofisocyanates and diisocyanates and polymeric diisocyanates such as thosehaving the general formula:

[Q( )ils in which i and j are integers of two or more, as well as (asadditional components in the reaction mixtures) compounds of the generalformula in which i is one or more and L is a monofunctional orpolyfunctional atom or radical. Examples of this type includeethylphosphonic diisocyanate,

phenylphosphonic diisocyanate, C H P(O) (NCO) compounds containing a=SiNCO group, isocyanates derived from sulfonamides (QSO NCO), cyanicacid, thiocyanic acid, and compounds containing a metal NCO radical suchas tributyltin isocyanate.

The polyisocyanates are preferably employed in this invention in amountsthat provide from of 110% of the stoichiometric amount of isocyanatogroups required to react with all of the hydroxyl groups of thepolyester or polyether and with any water present as a blowing agent.

The blowing agents employed in this invention include water, methylenechloride, liquefied gases which have boiling points below 80 F. andabout 60 F., or by other inert gases such as nitrogen, carbon dioxide,methane, helium and argon. Suitable liquefied gases include saturatedaliphatic fluorohydrocarbons which vaporize at or below the temperatureof the foaming mass. Such gases are at least partially fluorinated andcan also be otherwise halogenated. Fluorocarbon blowing agents suitablefor use in foaming the formulations of this invention includetrichloromonofiuoromcthane, dichlorodifiuoromethane,dichlorofluoromethane, 1,1-chloro l fluoroethane, 1-chloro-l,l-difluoro,2,2'dichloroethane, and 1,1,1-trifluoro, 2-chloro-2-fluoro, 3,3-difluoro4,4,4 trifluorobutane. The amount of blowing agent used will vary withdensity desired in the foamed product. Usually from 2 to 15 parts byweight of the blowing agent per parts by weight of the polyester arepreferred.

Other additional ingredients can be employed in minor amounts inproducing polyurethane foams in accordance with the process of thisinvention if desired for specific purposes. Thus, Inhibitors (e.g.d-tartaric acid and tertiarybutyl pyrocatechol, Ionol) can be employedto reduce any tendency of the foam to hydrolytic or oxidativeinstability. Compounds containing both secondary and tertiary hydroxylgroups, such as hexylene glycol [i.e. 2-methyl-2,4-pentanediol], can beused to further reduce compression set and to solubilize aminecatalysts. Fatty acids, such as those in tall oil (a by-product from thedigestive process of fine wood chips composed of fatty acids, rosinacids and polymerized, unsaponifiable hydrocarbons), can be employed tosolubilize insoluble amine catalysts. Parafiin oil can be added toregulate cell structure so as to coarsen cells and thereby furtherreduce the tendency of the foam to split. Other additives that can beemployed are dyes or pigment and anti-yellowing agents.

In producing polyester polyurethane foams in accordance with thisinvention, conventional organic surfactants (emulsifiers) can beemployed in combination with the siloxane-oxyalkylene block copolymer asfoam stabilizers. Such organic surfactants include liquid,waterinsoluble organic compounds having at least 18 carbon atoms and atleast one carbon-bonded sulfonic acid group represented by the formula:

or at least one ammonium, alkali metal or alkaline earth metal saltgroup derived from said sulfonic acid group. The sulfonic acid groups orsalt derivatives thereof can be substituents on any of a wide variety ofbackbone organic compounds provided such compounds have at least 18carbon atoms and are water-insoluble liquids. Preferably, such groupsare substituents on hydrocarbons (on a mixture of hydrocarbons), fattyacid esters or hydrocarbons having polyalkylene oxide substituents. Thesulfonic surfactants can have viscosities up to about 1,400 SUS at 210F. or higher. Suitable sulfonic surfactants include Witco Formez 77-86and Erncol H-77. Preferred sulfonic surfactants are liquid,water-insoluble materials having the formula:

wherein R is a monovalent hydrocarbon group having at least 18 carbonatoms, M is a cation selected from the group consisting of the hydrogen,NR alkali metal and alkaline earth metal cations, R is hydrogen or amonovalent hydrocarbon group, and m is the valence of the cationrepresented by M. The sulfonic surfactants represented by Formula lainclude hydrocarbyl sulfonic acids and the ammonium, quaternaryammonium, alkali metal and alkaline earth metal salts thereof.Surfactants of the latter type are described in Bryton Sulfonatcs, 1962,Bryton Chemical Company, 50BR4762.

Conventional polyurethane-foaming catalysts are employed in thisinvention.Thus, in the case of polyester polyurethane foams, usefulcatalysts include N-methyl morpholine, N-ethyl morpholine, hexadecyldimethylamine, dimethyl benzyl amine, and N-cocomorpholine and the like.Such catalysts are preferably employed in an amount from 0.1 to 0.5 or 2weight percent based on the total weight of the polyester and thepolyisocyanate. Amines are preferred. In the case of polyetherpolyurethane foams, useful catalysts include amines and a wide varietyof metal compounds, both inorganic metal compounds and metal compoundswhich contain organic groups. Particularly useful catalysts are tertiaryamines and organo-tin compounds. All of the above catalysts can be usedalone or in mixtures with one or more of the other such catalysts. Amongthe organo-tin compounds that deserve particular mention as catalysts inproducing polyether polyurethane foams in accordance with this inventionare stannous acylates such as stannous acetate, stannous octoate,stannous laurate, stannous oleate and the like; stannous alkoxides suchas stannous butoxide, stannous 2-ethylhexoxide, stannous p'henoxide,omand p-stannous cresoxides, and the like; dialkyl tin salts ofcarboxylic acids, e.g., dibutyltin diacetate, dibutyltin dilaurate,dibutyltin maleate, dilauryltin diacetate, dioctyltin diacetate, and thelike. The tertiary amines which are useful as catalysts in producingpolyether polyurethane foams in accordance with this invention includetertiary amines substantially unreactive with isocyanate groups andtertiary amines containing active hydrogen atoms reactive withisocyanate groups. Typical tertiary amines which are substantiallyunreactive with isocyanate groups include triethylamine, tributylamine,trioctylamine, N-methylmorpholine, N-ethylmorpholine andN-octadecylmorpholine (N-cocomorpholine). Typical teriary aminescontaining active hydrogen atoms reactive with isocyanate groups includedimethylethanolamine, triethanolamine, triisopropanolamine andN-methyldiethanolamine. Other suitable catalysts include metal organiccompounds of lead, arsenic, antimony, and bismuth compoundscharacterized by the presence therein of a direct carbon-tometal bond;organic halides of titanium; the inorganic halides of tetravalent tin,arsenic, antimony, bismuth and titanium; polystannates; tin, titaniumand copper chelates; and mercury salts. In general, the amount of eachcatalyst employed is preferably between about .2 and about 1.0 part byweight per parts by weight of polyether or polyester.

The amount of the siloxane-oxyalkylene block copolymer employed as afoam stabilizer in this invention can vary over wide limits. Thus fromabout 0.2 weight percent to 10 weight percent or greater of the blockcopolymer can be used (Weight percentages are based on the total weightof the foam formulation, that is, the polyether or polyester,isocyanate, catalyst, blowing agent and foam stabilizer). There is nocommensurate advantage to using amounts of foam stabilizer greater thanabout 10 weight percent. Preferably, the amount of siloxane-oxyalkyleneblock copolymer present in the foam formulations varies from about 0.5weight percent to about 2.0 Weight percent.

As is apparent from the foregoing description, the relative amounts ofthe various components reacted in accordance with the above-describedprocess for producing flexible polyester or polyether,polyurethane/foams in accordance with this invention are not narrowlycritical. The polyester or polyether and the polyisocyanate, takentogether, are present in the foam formulations (reaction mixtures) usedto produce such foams in a major amount. The relative amounts of thesetwo components is the amount required to produce the urethane structureof the foam and such relative amounts are Well known in the art. Theblowing agent, catalyst and surfactants are each present in the knownamount necessary to achieve the function of the component. Thus, theblowing agent is present in a minor amount sufficient to foam thereaction mixture, the catalyst is present in a catalytic amount (i.e. anamount sufficient to catalyze the reaction to produce the urethane at areasonable rate) and the novel block copolymer surfactants are presentin a foamstabilizing amount (i.e. in an amount sufiicient to stabilizethe foam).

Polyurethane foams are produced in accordance with this invention by theconventional one-shot or one-step process. Typically this processcomprises (1) combining at a temperature between about 15 C. and about50 C. separate mixtures comprising (i) a polyether or polyester, thesiloxane-oxyalkylene block copolymer, a catalyst and blowing agent, and(ii) an organic isocyanate (or mixture of organic isocyanates) and (2)maintaining the combined mixture at a temperature between about 15 C.and about 50 C. until the foaming reaction commences, (3) pouring thefoaming reaction mixture into a suitable mold maintained at betweenabout 15 C. and about 50 C., and (4) curing the resulting foam byheating the foam at a temperature between about 100 C. and about C.

The heating step (4) described in the preceding paragraph is notessential, but heating cures the foamed product to a stable, tack-free,resin foam capable of sup porting a load within a relatively shortperiod of time (in the order of about five minutes to thirty minutes),whereas longer times are required to obtain a cured, tackfree resin atroom temperature. Also, the pouring step (3) is not essential since themixtures (i )and (ii) can be combined and the foaming reaction commencedand completed in a mold.

The siloxane-oxyalkylene block copolymers of this invention areremarkably more potent than various other siloxane-oxyalkylene blockcopolymer, including commercially available block copolymers. That is, alesser amount of the novel copolymers is required to stabilizepolyurethane foam. Accordingly, economic advantages result from the useof the novel block copolymer. This superiority is surprising in view ofthe teachings of the art that, among block copolymers having the generallinear structure of Formula A above, those having 6 to 30dimethylsiloxane units are preferred (the novel block copolymer of thisinvention have a minimum of 40 of such units).

In addition, the block copolymers of this invention can be admixed withwater and stored for prolonged periods and then used as foam stabilizersto produce breathable flexible polyether polyurethane foam. This cannotbe done with certain known hydrolytically stable siloxaneoxyalkyleneblock copolymers. Further, the novel block copolymers are produced fromreadily available silanes and have good tin operating latitude.

Still further, the novel block copolymers provides for processingadvantages in the production of polyurethane foam in that they allow forthe use of a lower viscosity surfactant system. Current processesinvolve the pumping of a standard volume of a block copolyrnersurfactant and, the more viscous the surfactant, the more diflicult isthe pumping operation. It is not feasible to dilute the conventionalviscous copolymers with a solvent to produce a lower viscosity solutionsince this would require the handling and pumping of undesirably largeand nonstandard volumes of liquids. However, the novel block copolymersof this invention, due to their greater potency, can be diluted withsolvents to produce relatively low viscosity solutions of standardvolume and the same effectiveness as conventional surfactants. Suitablesolvents are organic liquids in which the block copolymers monovalenthydrocarbon group such as defined for Z and t has a value of at least 2.When Z is hydrogen, it is preferred that the ZO(HO) group represent nomore than 5 weight percent of the solvent. Preferably some or all of thegroups represented by Z'O are ethyleneoxy groups to impart watersolubility to the solvent. The copolymer-solvent solutions preferablycontain from 25 to parts by weight of the copolymer per parts by weightof the solvent and the copolymer but can contain from 1 to 99 parts ofthe copolymer. Such copolymersolvent solutions can also contain smallamounts of organic surfactants (e.g. C H C H (OC H OH) to raise thecloud point of aqueous solutions produced by mixing thecopolymer-solvent solution with water.

The flexible polyurethane foams produced in accordance with thisinvention can be used in the same areas and for the same purposes asconventional flexible ester urethane foams (e.g. they can be used ascushioning materials for seating and for packaging delicate objects, asgasketing material and, in the case of foams produced from polyesters,as textile interliners).

The following examples illustrate the present invention.

In the examples appearing below, copolymers A to W are copolymers ofthis invention within the scope of Formula A above Whereas Copolymers Ito V1 are other siloxane oxyalkylene copolymers (e.g., commerciallyavailable copolymers) used for purposes of comparison. Me is used todenote the methyl group.

Examples I to III illustrate the preparation of the block copolymers ofthis invention.

EXAMPLE I A silicone fluid of average composition 72( SiMe (48.5 grams,0.043 mole of SiH), an allyl-end-blocked polyether of averagecomposition M60 29 2qcH2CH CH2 (143 grams, 0.047 mole of allyl), toluene(94 milliliters) and chloroplatinic acid (25 parts per million as Pt)were stirred and heated to 85 C. The reaction mixture became clear andonly a trace of residual silanic hydrogen could be detected. Sodiumbicarbonate (2 grams) was added and the mixture sparged with nitrogen atC. and filtered. The copolymer obtained was a clear liquid with aviscosity of 25 C. of 3420 centistokes. 'The average composition of thesurfactant (copolymer A) was are soluble. Such liquids are of lowerviscosity than the block copolymer (e.g. they have viscosities less than900 centistokes at 15 C.). These liquids are desirably of low volatilityto minimize fire hazards (e.g. they should have boiling points greaterthan C. at atmospheric pressure). The solvents are preferablywater-soluble to permit premixing the solvent-copolymer solution withthe water often used in making the foam. 'Ihese solventcopolymersolutions can also be pre-imixed with the polyether (polyol), catalystsor organic blowing agent. Suitable solvents include ethers, esters,hydrocarbons and halohydrocarbons. Preferred liquids are compoundshaving the formula:

Z0 (Z'0) Z" wherein Z is hydrogen or a monovalent hydrocarbon group(e.g. alkyl such as methyl and ethyl, aryl such as phenyl and tolyl,aralkyl such as benzyl, or alkenyl such as vinyl), Z is an alkylenegroup (e.g. an ethylene, propylene, butylene, amylene or octylenegroup), Z" is a EXAMPLE II A solution of a hydrosiloxane of averagecomposition Me Si0(Me SiO) (MeHSi0) ,SiMe (37.9 grams, 0.072 mole ofSiH) and toluene (86 g.) was heated to 70 C. in a 500 milliliter flaskequipped with stirrer, thermometer, dropping funnel, heating mantle andcondenser. Chloroplatinic acid catalyst (25 parts per million Pt) wasadded. A polyether of average composition M60 5 CH2CH=CH3 9 EXAMPLE 111Using the procedure of Example I surfactants of this invention wereprepared which had the following compositions:

Generic formula Me Life Me=Si (MezSiOLI eO (iJHCHzO)...(CHQCHzOLJhHSiOhSiMc;

- Viscosity x y m(P0) n(11.0) cstk., at 25 C 87 6. 7 29 20 3, 060 75 12.4 17 12 .870 73 4. i. 29 20 4, 000 69 9. 1 29 20 1, 670 71 9. 1 39 17 1,280 71 6. 7 30 29 3,610 73 4. 1 30 29 9, 200 71 6. 7 34 24 1, 930 75 12.4 19 18 1, 240 71 6. 7 22 21 2, 640 72 5. 1 29 20 2, 501 87 6. 5 29 203, 210 73 4. 0 29 20 4, 340 88 5. 7 29 2o 4, 750 42 3. 6 29 20 1, 620 484. 2 29 .20. I 1, 700 49 3. 7 29 20 2, 100 125 9. 1 29 20 4, 540

1 PO denotes proplyene oxide units. 3 E0 denotes ethylene oxide units.

Also using the procedure of Example 1, two additional copolymers of thisinvention having the following formulae were prepared:

EXAMPLE IV Flexible polyether polyurethane foams were prepared from thefollowing materials:

Material: Parts by weight Polyether having a hydroxyl number of 5 6produced by reacting glycerol and propylene oxide 100 Triethylenediamine 0.1 N-ethylmorpholine 0.2 Water 3.5 Stannous octoate 0.4Siloxane-oxyalkylene block copolymer as shown in Table I 0.38 CFCl 8.0Tolylene diisocyanate 43.1

The copolymers used and the properties of the foams produced are shownon Table I.

TAB LE I Foam r0 erties subscripts in formula p p x (number y (number inExample III To of MezSiO 0t polyether Rise collapse Copolymer units)chains) In (P O) n (E 0) (inches) (inches) CPI Shown for purposes ofcomparison, not a eopoly'mer of this invention.

tactant.

Examples IV to IX illustrate the production of flexible polyetherpolyurethane foam in accordance with the process of this invention. Inall cases, conventional mixing, foaming and curing procedures were used.In brief, the reactants were mixed and then the foaming and urethaneforming reactions occurred without the application of external heat.Generally, the block copolymer and the polyether (polyol) were mixedfirst. To this mixture was added the water and amine catalyst(s) andthen the fluorocarbon blowing agent was added. The mixture so formed wasstirred for 15 seconds and then the tin catalyst was added and themixture was again'stirred for 8 seconds. Finally the polyisocyanate wasadded and the reaction mixture was poured into a box. Modifications ofthis mixing sequence are shown in the examples. Thereupon the foam wascured by heating in an oven for 15 minutes at 130 C. The performance ofthe novel copolymers as compared with the performance of othercopolymers as foam stabilizers is shown in the tables presented below.

For the sake of brev ty, the following abbreviations l Commerciallyavailable hydrolyzable siloxane-oxyalkylene block copolymer polyurethanefoam sur- EXAMPLE V Flexible polyether polyurethane foams were preparedfrom the following materials:

Material: Parts by weight Polyether having a hydroxyl number of 5 6produced by reacting glycerol and propylene oxide 100.0N,N,N',N'-tetramethyl-1,3-butanediamine 0.1 N-ethylmorpholine 0.2 Water4.0 Stannous octoate 0.3 Siloxane-oxyalkylene block copolymer as shownin Table II (0.6 part by weight used for Copolymers IV and D) 0.3Tolylene diisocyanate 49.5

In all cases the block copolymer was premixed with the water prior toforming the reaction mixture with the remaining materials indicatedabove. The copolymers used and the properties of the foams produced areshown on Table II.

TABLE 11 Foam properties Subscripts in formula x (number y (number inExample 111 Top of MezSiO of polyether Rise collapse Copolymer units)chains) in (P) 11 (E 0) (inches) (inches) CPI Shown or purposes ofcomparison; not a coploymer of this invention.

Commercially available non-hydrolyzable coploymer having an acyloxyend-blocking group in the oxyalkylene block.

7 0. 6 Part by weight.

EXAMPLE VI 0.35 )g 0.60:0.21 part by weight of these copolymers wereFlexible polyether polyurethane foams were prepared used.) The amount ofstannous oetoate used was 0.35 part from the materials indicated inExample V using the 0 by weight. The amounts of the other materials wereas in copolymers shown in Table III below. Copolymer I was Example IV.In all cases, the copolymer or copolymer used in an amount of 0.3 partby weight. The other cosolution was premixed with the polyether beforeforming polymers were used in an amount of 0.22 part by weight. thereaction mixture. Table IV also shows the properties The amounts of theother materials were as in Example of the foams produced.

TABLE IV Foam properties subscripts in formula x (number y (number inExample III Top of MezSiO oi polyether Rise collapse Copolymer units)chains) to (P0) 11 (E0) (inches) (inches) CPI 19 3 19 2.3 4.5 as 3 1 297.3 0.7 32 72 5 1 29 20 7 7 0.6 34 73 4 0 29 20 7 2 0. 6 3s 37 6 1 29 207 7 0.3 34 as 5 7 29 20 7 s 0.3 36 125 9 1 29 20 7 6 0. 5 3s Shown forcomparison only; not a copolymer of this invention.

1 Copolymer in solution containing 60 wt. percent copolymer and 40 wt.percent H0 (0 1140) w(CaHa0)uC4Ha.

Z Copolymer in solution containing 60 wt. percent copolymer, 36 wt.percent HO(C1H4O);9(C;H;O);4C4H9 and 4 wt. percent CaHiDCsHKOCiHOu-aOH.

V. Table III also shows the properties of the resulting The results inTable IV illustrate that the copolymers foams, of this invention areconsiderably more potent, even at TABLE III Foam properties subscriptsin formula x (number 37 (number in Example III Top of MezSiO oipolyether Rise collapse Copolymer units) chains) in (P0) n (E0) (inches)(inches) GP! Shown ior comparison only; not a copolymer of thisinvention.

The data in Table III illustrates that, although copolymarkedly lowerconcentrations, than the commercially mers of this invention havingbetween and 50 dimethylavailable copolymer. The results also illustratethat the siloxane units are more potent than the commercially novelcopolymers are superior to a seemingly similar coavailable copolymereven at markedly lower concentrapolymer having fewer dimethylsiloxaneunits.

tions, still better results are obtained with those copoly- EXAMPLE VIIImers having at least such units.

Polyurethane foams were prepared from the materials EXAMPLE VIIindicated in Example IV using the copolymers shown in Table V below.Copolymer V, the 60 wt. percent copoly- Polyurethane foams were preparedfrom the materials 70 mer solutions and the stannous octoate were eachused in indicated in Example IV using the copolymers shown in an amountof 0.35 part by weight. Accordingly, the co- Table IV below. CopolyrnerI was used as such in an polymers added as solutions were used in theamount of amount of 0.38 part by Weight. The other copolymers 0.21 partby Weight (0.35 .6=0.2l). The amounts of the were employed as 60 wt.percent solutions which were other materials were as indicated inExample IV. Table used in an amount of 0.35 part by weight. (Hence Valsoshows the properties of the foams produced.

TABLE V Foam properties Subscrlpts in formula x (number y (number inExample 111 Top of MezSiO of polyether Rise collapse Copolymer units)chains) In (P) 11 (E0) (inches) (inches) CPI Shown for comparisonpurposes only; not a copolymer of thE invention. 1 Copolymer in solutioncontaining 60 wt. percent of the copolymer and 40 wt. percent HO(C:H4O)1o(C3- Copolymer in solution containing 60 wt. percent of thecopolymer, 36 wt. percent HO(CiH4O) (CaHtO )m The data in Table Villustrates the high potency of the novel copolymers of this inventioneven at low concentration.

EXAMPLE IX This example illustrates the ability of copolymers of thisinvention to produce open cell polyurethane foam after prolonged storagein aqueous solution. This prop erty is remarkable in view of the poorperformance of certain allegedly hydrolytically stable, known copolymersafter storage under the same conditions. The copolymers used wereCopolymer M of this invention and a commercially available knowncopolymer (Copolymer VH). The composition of Copolymer M is shown inExample III above. Analysis of Copolymer VII indicate it to be similarto Copolymer M. However, Copolymer VII has an acetoxy endblocking groupon each oxyalkylene block where a Copolymer M has methoxy endblockinggroups.

Copolymer VII was used as such (100% copolymer) while Copolymer M wasused in solution [the solution contained 60 weight percent of CopolymerM, 36 weight percent Of HO(C2H4O)19(C3H50)14C4H9 and 4 Weight percent ofthe reaction product of one mole nonylphenol and 14.5 moles of ethyleneoxide having the formula 9 1s s 4( 2 4) 14.5

Aqueous solutions of the copolymers were prepared and stored. Theaqueous solutions contained:

Material: Grams Copolymer VII or solution of Copolymer M 100 Distilledwater 350 Triethylene diamine N-ethyl morpholine After storage forvarious periods of time, portions of the aqueous solutions were used inproducing flexible polyether polyurethane foams using the materials andamounts of materials set forth in Example IV above. The breathability(which is directly proportional to the amount of open cells in thefoams) of the foams was measured using a standard air permeabilitytechnique. In this technique, air is forced through a 2" x 2" x 1" blockof foam at a pressure differential of 0.5 inch of water. The volume ofair passing through the block in a given time (standard cubic feet ofair per minute) is directly proportional to the breathability (amount ofopen cells) in the foam. Table VI below shows the results obtained.

TABLE VI Rate of flow of air through foam (standard cubic feet perminute) Foams produced Foams produced Storage time (hours) copolymer VIIcopolymer M The results in Table VI shows that prolonged storage inaqueous solution had no effect on the performance of Copolymer M butdrastically impaired the performance of Copolymer VII.

EXAMPLE X Solvent viscosity (centistokes at 25 C.)

Solution viscosity (centistokes at 25 C.)

Copolymer M has a viscosity of 2510 centistokes at 25 C. The greaterpotency of this copolymer allows for the use of the above relatively lowviscosity solutions in lieu of an equal volume of 100% solids ofconventional lower potency surfactant.

The copolymers not of this invention presented in the tables above forpurposes of comparison (i.e., Copolymers I to VI) are shown in thetables as represented by the generic formula in Example III for ease ofcomparison. Actually, these copolymers may not have the exact structureof the generic formula. This is particularly the case for Copolymer Iwhich is within the scope of the claims of US. Patent 2,834,748.

What is claimed is:

1. A liquid siloxane-oxyalkylene block copolymer represented by theformula:

wherein R' is a monovalent hydrocarbon group containing from 1 to 10carbon atoms, R is an alkylene group containing at least 2 carbon atoms,m and n are numbers, the sum of mr+n is such that the oxyalkylene block,RO(C H O) (CgH O) has a molecular weight of at least 1500, from 15 to 60weight percent of the oxyalkylene units are oxyethylene units, x has avalue of at least 40, y has a value of at least 3, the siloxane blockconstitutes from 15 to 70 weight percent of the block copolymer, and Meis a methyl group.

2. The block copolymer of claim 1 wherein x has a value of at least 50.

3. The block copolymer of claim 1 wherein x has a value of at least 70.

4. The block copolymer of claim 1 wherein x has a value from 50 to 200.

5. The block copolymer of claim 1 wherein x has a value from 70 to 125.

15 16 6. The block copolymer of claim 1 wherein x has a FOREIGN PATENTSvalue from 70 to 150 inclusive, y has a value from 4 to 95 33 10 19 4 c15, R contains 3 carbon atoms and R is an alkyl group 955,915 4 19 4Great i i containing from 1 to 4 carbon atoms. 954,041 4/1964 GreatBritain.

5 1,015,611 1/1966 Great Britain. References Cited TOBIAS E. LEVOW,Primary Examiner UNITED STATES PATENTS P. F SHAVER, Assistant Examiner2,846,458 8/1958 Haluska. 3,398,104 8/1968 Haluska 260-4482 X 3,402,1929/1968 Haluska. 2-60-25, 46.5, 33.6, 33.2, 29.2

